Thanks, I included a footnote to elaborate on this. There's actually a paper on how Cephalon produces R-modafinil because they can't just directly synthesize one of the enantiomers. It seems the process does produce both enantiomers (but more R than S ?).. I don't fully understand the process but they have a way of crystalizing out the S enantiomer of modafinil acid and using HPLC..